Grinder attachment for brake relining machines



Feb. 27, 1934-. BARRETT 1,949,070

GRINDER ATTACHMENT FOR BRAKE RELINING MACHINES Filed Jan. 11, 1932 .21 F 9 "1mm INVENTOR,

ATTORNEY Patented Feb. 27, 1934 UNITED STATES PATENT OFFICE RELINING Harry B. Barrett,

Application January 11,

'7 Claims.

This invention relates generally to brake relining machines and, more particularly, to a certain new and useful improvement in machines for grinding the applied or attached lining of a brake-shoe, brake-band, or the like.

The introduction upon automobiles and trucks of four-wheel brakes necessitated a reduction by approximately one-half of the cam leverage exerted on each brake by the actuating foot-pedal, the foot pressure exerted by the driver being substantially the same with four-wheel brakes as formerly with merely rear or two-wheel brakes. This relatively great reduction in cam or leverage action, in turn, required of necessity a closer fitting of the internal shoe or the external band to the drum to obtain the proper braking action, the present normal clearance between the shoe or band and the drum being exceedingly limited and frequently not exceeding .010 thousandths of an inch. Consequently the attached lining of the shoe or hand must be smooth, even and without high spots, and have a curvature conforming to the curvature of the particular drum to obtain the correct amount of braking power to each respective brake. Also the several brakes of a set should be equalized to effect an evenness in braking action, for, should, on application, more frictional resistance be effected by one shoe or band than the others, an unevenness in braking action, as is well known, will follow, causing the car to swerve to one side or the other resulting not only in unevenly worn tires, but frequently also in serious accidents.

My present invention has hence for its chief object the provision of a machine for grinding an attached brake lining to a substantially smooth, even surface and also to a curvature conforming to the curvature of the brake drum with which the shoe or band is to frictionally engage.

My invention has for a further object the provision of a machine of the kind and for the purpose stated which is simple and inexpensive in structure, which may be readily and conveniently operated, and which is efiicient in the performance of its intended functions.

And with the above and other objects in view, my invention resides in the novel features of form, construction, arrangement and combination of parts hereinafter described and pointed out in the claims.

In the accompanying drawing:

Figure 1 is a fragmentary side elevation of a grinding machine of my invention, shown in connection with a brake shoe and its attached brake lining,

MACHINES Los Angeles, Calif.

1932. Serial No. 585,881

Figure 2 is a similar view of the machine showing parts thereof disposed for contact with the lining of a brake band,

Figure 3 a fragmentary view of the machine, looking in the direction of the line 3--3 of Figure 1, and

Figure 4 is a cross sectional view of the machine taken approximately on the line 4--4, Figure 2.

Referring now more in detail and by reference characters to the drawing, which illustrates a preferred embodiment of my invention, 1 is a pedestal adapted to support a platform 2, which carries a bracket 3, to which is secured a suitable motor 4. I have shown at 5, 6 and 7, elements which are described in Letters Patent for Brake relim'ng machines, No. 1,882,109, issued to me on October 11, 1932, and which elements perform a useful function in providing a brake relining and brake finishing machine, which is inexpensive of manufacture and combines in one compact machine every essential necessary for a proper and workman-like relining job. Reference is made to said patent for details of the elements just mentioned.

The finisher or grinder constituting the presso cut invention includes a bracket 8 provided with a pair of spaced furcations 9 and 10, which are transversely screw-threaded to receive pivot-bolts 11 and 12. The bracket 8 is formed with a recessed or half-round portion 13, and adapted for cooperation with the part 13 is a complementary half round portion 14 provided with flanged ends 15 and 16. Bolts 17 and 18 are adapted to hold the half rounds 13, 14 in position of cooperation and in such a manner that the pedestal 1 is gripped between said members 13 and 14. Both flanges 15 and 16 are transversely split, as at 19 for one of said flanges, such arrangement allowing ready assemblage of the parts in position for engagement with the bolts l7 and 18 and their securing nuts.

Supported by and bet-ween the pivot-bolts 11, 12 for relative up and down swinging movement, is a member or block 20, which includes a part 21 bored to provide a journal or box for supporting a spindle or shaft 22, which in turn isadapted to removably carry at one end a roller 23 and at its opposite end a wheel 24. The block 20 also includes a bracket or fiange 25, which is preferably integrally formed with, or disposed substantially transverse to, the journal or bearing 21. The bracket or flange 25 is bored transversely, as at 26, adjacent the periphery of the roller 23, and is also provided with a pair of lateral ears '2? and 28..

An arm 29 of lengthwise arcuate or segmental configuration, as best seen in Figure 1 is pivotally mounted at its one or inner end on a bolt 31 disposed in the bore 26 of the standard or bracket 25, and fixed to, and extending transversely or laterally from the spaced inner and outer ends of arm 29 in approximately parallelism with each other and with the axis of the roller 23, are supporting bars 32, 33, the arm 29 having a length greater than the diametrical dimension of the Wheel 23.

The ears 2'7, 28 are transversely screw-threaded for the reception of adjusting-screws 34, which preferably have coil springs 35 surrounding a portion thereof, whereby, when the screws 34 are moved relatively to the threads of their supporting ears, the coil springs 35 will exert pressure to prevent undesired movement thereof.

Thus the arm 29 may selectively be swingably shifted to occupy either of the respective positions illustrated in Figures 1 and 2. In other words, the arm 29 and its lateral bars 32 and 33 provide means for accurately and adjustably supporting the work relatively to the roller 23.

The wheel 24 may be formed of any suitable material, such as rubber or the like, and may be mounted in any suitable manner upon the shaft 22, such as by means of a collar 36 carrying a screw adapted to engage a flattened portion on the shaft.

The motor 4 carries upon its shaft a friction disc 3'7, and the wheel 24 and friction disc 37 are adapted for coengagement to turn the shaft 32 and rotate the roller 23 when the motor is in operation.

In Figure 3 is illustrated a specific means for maintaining the wheel 24 out of engagement with disc 3'7. Such means includes a member 38 depending preferably integrally from the member 21, and swingably mounted on a bolt 40 passed through a transverse opening in the member 38, is what may be termed a release arm 39. Also secured between the head of the bolt 40 and the bracket 8, is a coil spring 41, which at all times tends to urge the members 24 and 37 into coengagement; the member 20 being swingably supported by the pivot bolts 11, 12. In order that undue strain should not be imposed upon the shafts of both the motor and the roller, means 42 is provided which constitutes an adjusting nut adapted to lie between the members 8 and 38. In this instance, the adjusting nut is carried by the member 8. When it is desired to disengage the wheel 24 from the disc 37, the member 38 is grasped and pulled outwardly, which movement will be resisted by the spring 41 until a position is reached where the arm 39 will lie between the adjusting nut and the member 38. Obviously moving the arm 39 from its position between the adjusting nut and the member 38 will allow the parts 24 and 37 to again engage.

The roller 23 is adapted to carry on the periphery thereof an abrasive substance 43, which may take the form of sandpaper or other ma terial.

The arm 29 and its supported bars 32, 33 are thus adapted to support the work at two spaced points on an are relatively to the grinding wheel 23 and concentric also with the curvature of the particular drum. Hence, in use and operation, the attached lining L of a brake-shoe 44, as illus'trated in Figure 1, is to be ground to a smooth surface and also to such thickness to provide proper clearance for effecting the proper frictional engagement with the drum of the brake.

The arm 29 is disposed as illustrated in Figure 1 with its free end presented away from the wheel 23, the members or bars 32, 33, being then both disposed radially to one side of the axis of the wheel 23. Then by means of the adjusting screw 34, its said free end is adjustably shifted upwardly or downwardly, reference being made to Figure 1, so as not only to increase or decrease the engaging relation between the roller 23 and the lining L when the brake-shoe 44 is rested upon the two spaced points of support provided by the bars 32, 33, but also so that the arc defined by said spaced supports 32, 33, is approximately concentric with the curvature of the particular drum. The adjustment of the arm 29 being so effected, the brake-shoe 44 and its attached lining L are rested upon the bars 32, 33, and, as so supported on the now relatively fixed arc, reciprocated and shifted relatively to the rotating wheel 23 and the lining L thereby smoothed and evened, high spots, eliminated, and its thickness reduced as may be required to meet the operating conditions of the particular brake installation.

In like manner, the arm 29 is first swung crosswise over the wheel 23 for disposition as illustrated in Figure 2, of the bars 32, 33, upon angularly opposite sides of the wheel 23, and its outer free end similarly adjusted relatively to the wheel 23 and the diametrical dimension of the particular drum for effecting the proper grinding action upon the attached lining L of a brake-band 44, which, supported in a like manner by the spaced bars 32, 33, and the several parts being so relatively adjusted, is rotarily shifted around the rotating wheel 23 and its attached lining L ground to a smooth, even surface and to the desired thickness.

As best seen in Figures 1 and 2, the bracket 25 is slotted adjacent the ears 27, 28, concentrically with the axis of the wheel 23 for adjustably accommodating the outer bar 33 in its respective work-supporting positions.

The machine is hence selectively adapted to equally well function in connection with the attached lining of either an internal shoe or an external band, and by my machine the several attached linings of a brake-set may with ease, convenience, and precision, be uniformly ground for effecting both the desired, as well as the equalization of, braking action of the several brakes of the set.

It is to be understood that changes and modifications in form, construction, arrangement, and

combination of the several parts of the machine may be made and substituted for those herein shown and described without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A grinding-machine including, in combination, a frame, a grinding-wheel mounted for rotation on the frame, an arm pivotally attached at an end'to the frame adjacent to the wheel, the arm having a length greater than the diametrical dimension of the wheel, and members extending laterally from the spaced outer and inner ends of the arm for supporting the work for engagement by the wheel, the arm being swingably adjustable with respect to the wheel for disposing said members on opposite sides of the axis of the wheel.

2. A grinding-machine including, in combination, a frame, a grinding-wheel mounted for rotation on the frame, a lengthwise arcuate arm pivotally attached at an end to the frame adjacent to the wheel, the arm having an arcuate length greater than the diametrical dimension of the wheel, and members extending laterally from the inner and outer ends of the arm in approximate parallelism witheach other and with the axis of the wheel for supporting the work for engagement by the wheel, the arm being swingably adjustable with respect to the wheel for disposing said members on opposite sides of the axis of the wheel.

3. A grinding-machine including, in combination, a grinding-wheel, a lengthwise arcuate arm pivotally mounted at an end adjacent to the wheel and having a length greater than the diametrical dimension of the wheel, members extending in spaced relation laterally from the arm in approximate parallelism with each other and with the axis of the wheel for supporting the work for engagement by the wheel, the arm being swingably adjustable with respect to the wheel for disposing said members on opposite sides of the axis of the wheel, and an adjusting screw for retaining the outer end of the arm in adjusted position.

4. A grinding-machine including, in combination, a support, a grinding-wheel mounted for rotation on the support, an arm pivotally at its inner end arranged on the support adjacent to the wheel and having a length greater than the diametrical dimension of the wheel, bars extending laterally from the inner and outer ends of the arm in approximate parallelism with each other and with the axis of the wheel for supporting the work for engagement by the wheel, the arm being swingably adjustable with respect to the wheel for disposing said members on opposite sides of the axis of the wheel, and an adjusting screw on the support for retaining the outer end of the arm in adjusted position.

5. A grinding-machine including, in combination, a grinding-wheeel, an arm pivotally mounted at its inner end adjacent the wheel, and members extending in spaced relation laterally from the arm, the arm being swingable from and towards the wheel for disposing said members radially both to one side or individually upon angularly opposite sides of the axis of the wheel for selectively supporting a convexed or a concaved member for engagement by the wheel.

6. A grinding-machine including, in combination, a grinding-wheel, an arm pivotally mounted at its inner end adjacent to the wheel and having a length greater than the diametrical dimension of the wheel, and members extending laterally from the outer and inner ends of the arm, the arm being swingable outwardly from or crosswise of the axis of the wheel for disposing said members both radially to one side or individually upon angularly opposite sides of the axis of the wheel for selectively supporting a convexed or a concaved member for engagement by the wheel.

7. A grinding-machine including, in combination, a grinding-wheel, an arm pivotally mounted at its inner end adjacent to the wheel and having a length greater than the diametrical dimension of the wheel, members extending laterally from the outer and inner ends of the arm in approximate parallelism with each other and with the axis of the wheel, the arm being swingable outwardly from or crosswise of the axis of the wheel for disposing said members both radially to one side or individually upon angularly opposite sides of the axis of the wheel for selectively supporting a convexed or a concaved member for engagement by the wheel, and means for retaining the outer end of the arm in its selectively swung positions.

HARRY B. BARRETT. 

